Upgrade to commons-parent version 15

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/proxy/trunk@936207 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/pom.xml b/pom.xml
index 3dd3ce7..62eb4f0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -23,7 +23,7 @@
     <parent>
         <groupId>org.apache.commons</groupId>
         <artifactId>commons-parent</artifactId>
-        <version>14</version>
+        <version>15</version>
     </parent>
     <artifactId>commons-proxy</artifactId>
     <version>1.1-SNAPSHOT</version>